Pressure-relation gage



E. G. BAILEY.

PRESSURE RELATION GAGE.

APPLICATION men mm. a. |92|.

Reissued Apr. 12, 1921.

{Iv-o 25 readings of the gages ,will be the same navm o. BAILEY, or NEw'roN HIGHLANDS, nassacnusn'r'rs, AssIGNoa'ro slum E'IER COMPANY, A CORPORATION OF MASSACHUSETTS.

PRESSURE-RELATION GAGE.

Specification of Reissued Letters Patent. Reissued Apr. 12, 1921.

Original application flled March 21, 1911, Serial No. 616,020. Renewed August 24, 1917, Serial No.

188,067. Original No. 1,257,963, dated March 5, 1918.

Serial No. 450,032.

To all whom itmay concern:

Be it known that I, Envm G. BAILEY, a

a citizen of the United States, residin in Newton Hi hlands, in the county of iddlesex and, tate of--Massachusetts, have invented an Improvement in Pressure-Relation Gages, of which the following descripsame throughout, the operation of the instrument depending on a suitable combination and adjustment of two or more separate pressure-actuated gages, so that the either in actual magnitude or in comparison with graduations on a scale common to all the gages, when the pressures applied to the various parts of the instrument bear the desired relation to each other.

' While it is true that pressure gages of any suitableor usual construction may be used independently to indicate the pressures or difierencespfpressure in var ous parts of a conduitor passage, the time and trou ble involved in calculating from such indeendent readings, the relation which exists. between various pressures are such as to render such a procedure practically useless in obtaining the desired information. The instrument embodying this invention, however, is provided with means correlating two or more pressure gages so that they 45 show the same reading whena desired relation exists between the operating pressures and when the pressures are not equal, whereby the observer .can at all times see, by merely observing the readm s of the lnstrument, whether or not'the esired rela& tion exists between the various pressures applied thereto. Thednstrument also indiefinite' relation exists other Application for reissue filed March 8, 1921.

cafes in what manner and to what extent a change, if any, has taken place inthe relation between the pressures or pressure diffeiiz'ences for which the instrument has been se Figure 1 is a perspective view of an instrument having a plurality of reading tubes containing liquid subjected to pressure and a scale common to all; Fig. 2 is a front elevation of a similar instrument having a different arrangement of the reading tubes and scale; and Fig. 3 is a sectional diagram view of a further modification in which a pressure actuated pointer traveling over a scale is utilized as the equivalent of a rea'din tube. I

Beferrlng. to Fig. 1, the instrument is shown as prov1ded with three ordinary U- tube pressure gages 1, 2 and 3 which are mounted in guide grooves 4 and 5, the read ing leg of each U-tube being in front of a convergmgly, graduated scale 6. Pressures are communicated to the U-tube 1' which contains a liquid, through pipes 7 and 8 connected, respectively with the legs 9 and 10, the reading-leg 9 being located in front of the graduations 6. The U-tubes 2 and 3 are of similar construction, and the reading legs of saidtubes are located in front of the converging graduations 6, so that when the level of the liquid in each is even with or .proportionally distant from any one line of the scale, it indicates that a certain relation exists between the differences of pressure communicated to the tubes through the pipes-7, 8, 12, 13, 14 and 15.

As an illustration of the practical application of this gage, its use in connectlon with a gas fired boiler furnace will assist in explaining the invention. -nace it is desirable to supply more or less In such a fur-- gas to the furnace in pro ortion to. the amount of steam generated. t is also desirable to su ply air to the furnace in propo'r tion to t e amount of gas. supplied. In order that the attendant may know how to regulate the system in such a way as to maintain these desirable conditions, it is necessary to prov de him w1th.means whereby he may observe at all times the v conditions which actually exist, so-that he may be informed whens, departure from 8, 12 and 13, and 14 an a in the said steam conveying pipe, the tube the desired conditions has taken place, and may also be informed as to the nature and extent of the departure.

The instrument embodying this invention is'a telltale of the departure, if any, from the desired conditions, and is also an indi cator of the nature and extent thereof. In the construction shown in Fig. 1, Pitot tubes, or equivalent devices are placed in the conduits through which the fluids under observation are flowing, .and the dynamic and static pressure nozzles of each Pitot tube are connected, respectivel to pipes 7 and 15. If, for example, considering the areas of the pipes or conduits, the density of fluids, or. other elements affecting the result, it has been learned by comparative tests, .or other means, that for any given velocity head in the plpeconveying the steam from the boiler, the velocity head of the gas flowing to the furnace should be 70% of the velocity head 2 should beso placed with respect to the convergingly graduated scale, and to the .tube 1, that the difference between the pressure communicated through the pipe 12 and the} pressure communicated through the pi e 13 will be 70% of the difference between the pressure communicated through the pipe 7 and the pressure communicated through the pipe 8 when the surfaces of the liquids in the two tubes are coincident with, or proportlonally distant from any one line ofthe graduations, regardless of the part of the scale where the readings aretaken. It may also be assumed that, in a'similar way, it

has been learned what relation should exist between the velocltyhead in the air passage and the velocity head in the gas passage.

""Accordingly, the reading leg of the U-tube 3 should be so located with respect to the scale 6- and the U-tube 2 that the desired relation will exist when the liquid level in these tubes is coincident with, or propor: tionally distant from", an one line of the graduated-scale. It is o vious that when this instrument is properly constructed, adjusted, and connected to such a furnace, the observer can readily see whether or not the furnace is bei supplied with more or less gas than that w ich is in the desired proportion ,to the amount of steam being generated,

regardless of the rate of generation of steam; and in likemanner he can-also see whether or not too, much ortoo little air is being supplied to the furnace in proportion to the amount of gas. In practice, it may be desirableto supply proportionally more gas to the furnace for high rates of eneration of steam'than is necessary for ntermediate rates, in order to supply the additional heat required on account of the losses due to higher flue temperature, radiation, or other causes. If this change in re,-

lation has been determined, the converging graduations on the scale 6 are not necessarily focused at the point 16, as shown, and each graduation may be drawn at such an angle that the desired relation may be indicated for any rate of steam generation throughout the range desired. In likemanner, any other. varying proportion due to different rates of flow may be indicated by the level of the liquid in the U-tubes 2 and 3 by properly graduating the scale. This graduated scale constitutes the means correlatingthe several gages.

The particular advantage of the construction and arrangement above described is that the tubes are readily adjustable with respect to each other, so that if there is a change in the desired relation between the various pressures, an adjustment of the intrument to indicate the desired relation can readily be made. For example, it may be desirable to indicate, in a system where a plurality of boilers are used, whether or not an individual boiler is supplying to the main steam line, the desired proportional amount of steam. In such a case, it is practicable to connect the pipes 7 and 8 to the nozzles of a Pitot tube 1n the steam pipe leading from an individual boiler; and the level of the" liquid in the tube 1 will then vary with the.

rate of flow of steam through the said steam pipe. The pipes 12 and 13, in this case,

are connected to the nozzles of a Pitot tube in the main steam line, and the level of the liquid in the tube 2 will vary with the rate of flow of steam in the main steam line. For any givennumber of individual boilers in service, the tube 2 may be so located with relation to the convergingly graduated scale and with relation to the tube 1, that the liquid levels in the tubes 1 and 2 will coincide with, or be proportionally distant from,

the same line of the scale, when the individual boiler is supplying its desired quota of steam. This brings about a direct association with a main steam meter responsive to the output of steam froma battery of boilers, of anindividual meter responsive to the output from each single boiler, so that at each individual meter the reading thereof can becompared with the reading of the main meter to ascertain whether or not the individual-boiler is doing its proper i lation to the scale, so that the li uid levels in the two tubes will coincide wit or be at a proportional distance from, the same scale line when the new desired relation exists between the proportional rate of flow of steam in the two pipes.

Referring toFig. 2, a modified construction is shown, the instrument illustrated operating on the same principle as that of the instrument shown in Fig. 1, but being providedwith a difi'erently arranged system of indicating tubes. In this instrument, the

"adjustments provided for in the instrument shown in Fig. 1 are dispensed with; but the instrument is useful in cases where frequent changes in the desired relation between the various pressures are not required. The means correlating the several ga s is pro vided for in the size and shape 0 the reservoirs 17, 20, and 22, which as shownin the drawing are not alike as in ordinary gages, but are purposely made different to bring about a correlation of the readings when the desired relation'exists between the operating pressures. This feature, as will be seen, accomplishes exactly the same purpose as is accomplished by the converging graduated scale as shown in Fi 1.

The instrument il ustrated is provided with three modified U-tube pressure gages of the Plecet type. The pressure gage 17 18 consists of the reservoir 17 connected to the inclinedtube 18, and the pipes 170 and 180 connected to the gage, as shown, communicate pressures to the surface-of the liquid contained in the reservoir 17 and the The liquid contained in the tube 18, respectively. reater pressure in the tube 180 causes the liquid inthe tube 18 to move with respect to the scale 19 which is suitably graduated to denote the differenceof pressure measured by the said tube; Gages 20, 21 and 22, 23 are of similar construction.

For illustration, if this instrument were applied to a furnace burning solid fuel which is supplied with both primary and secondary alr, it could be determined what is the proper relation-existing between the drop in pressure across the fuel bed, the velocit head corresponding to the rate of flow 0 primary air, and the velocity head corresponding to the rate of flow of secondary air to the furnace. After this relation has been determined, the necessary relation between the areas of the reservoir and inclined tubes of the three parts of the ga e, together with the density .of li uid to e used in each, can be ascertaine so as to secure the corresponding relation between the. indicated. readings p 210, respectively, to the dynamic and static nozzles of a Pitot tube in the primaryair supply duct and the pipes 220,-and 230, respectively, to corresponding Pitot tube nozzles in the secondary air supply duct, a conditionis brought about whereby the extent of movement of the liquid in the three tubes 18, 21 and 23 will-be the same, so long asthe desired relation exists between the condition of the fuel bed and the proportional supply of primary and secondary air, regardless of the actual amounts of air, or. rates of flow. Conversely, any deviation from this relation will immediately change the level of the liquid in one tube with respect to another, thereby indicating to the observer that a change has taken place, and also indicating what adjustment is necessary .to restore the desired conditions.

The example above described is merely used as an illustration, and it is obvious that this instrument can be used for any number of purposes where similar indications are desired.

If, on account of any change in the character of fuel used, it is desirable to change the relation between the various differences of pressure under observation, the nece'ssary change can readily be made by varying the relative pressure receiving areas in the reservoir and the inclined tube of the modified U-tube gage which is connected across the fuel bed, so as to bring about the same indicated reading, although-in reality there is another difference of pressure across the fuel bed differing from that which previ ously existed for the same indicated read- 100 Tn the modified form of instrument shown in Fig. 3, the'indicatin devices are shown as pointers 24 and 25 w ich areadapted to 7 travel over a graduated scale 26, these point ers being the equivalent, in the use of the instrument, of the liquid in the reading tubes previously described, and being moved in response to differences in opposed pressures. In the construction shown, the pointer 24 is connected to a diaphragm 27 contained in a closed case 28 which receives the' opposed pressures at opposite sides of the diaphragm through pipes 29 and -30, so that the pointer 24 which is pivotedat 31 will-be 1115 moved over the scale when the diaphragm is moved. The pointer'25 is also pivoted at 31 and similarly connected with :1 diaphragm 32 in a closed case 33 which receives pressures at opposite sides of the dia hragm through pipes 34 and 35. The diap ragms .are so arranged and adjusted that, when the the same graduation on the scale 26, but will 1S0 not so coincide with the same graduation if the desired relation between the pressure diflerences has been departed from. So far as relates to the use of the instrument to indicate a departure from the desired relation,

it is obvious that the scale may be dispensed with, since, in this connection, either pointer is equivalent to a scale or means of comparison for the other.

From ,the foregoing description,it is apparent that the specific construction and arrangement of the pressure actuated devices used in obtaining the readings desired may be widely varied or modified ,without departing from the invention. The position of the pressure actuated indicators relative to each other and to the scale, however, is such in all cases that the said indicators will coincide with each other, or in some way indicate the same reading, solong as the predetermined desired relation between the pressures under observation exists, and will indicate that there is a departure from such relation when they do not so coincide.

This invention has proven particularly useful in connection with the operation of a steam boiler and furnace burning coal or other fuel. The pressure relation gage for this use consists of a differential pressure gagesuitably connected to the steam pipe, which gage gives a reading that varies as some function of the rate of generation of steam, combined with another differentialpressure gage, suitably connected to the air or gas passageway which gage gives a reading that varles as some function of the rate of air supply to the furnace; and the functional relations between the pressure dilferences and readings are such in the two cases that both gages indicate the same arbitrary readingwhen the most eflicient rate of air.

supply exists at all rates. of steam generation.

more liquidpressure gages, combined with What I claim is: 1. An instrument comprising two or more pressure gages provided with indicators, and

a means correlating said gages so that said indicators allindicate @e same reading when a desired relation other than the ratio of ,one as one exists between the various preshaving converging graduations, the gages and the scale being so located with relation to each other that the readings indicated by the levels of the liquid in the several gages will be proportionately distant from the same graduation of the said scale when a certain desired relation other than the ratio of one to one existsbetween various pressures.

3. A pressure relation gage comprising two or more pressure gages, the indicators of which are associated with a scale having converging graduations; and a support adjacent to the scale on which said pressure gages are movably mounted, whereby such an adjustment of the gage indicators relative to the scale can be made that the indicated readings will be proportionally distant from the same graduation of the scale when any desired predetermined relation exists between the pressures.

4. An instrument comprising two or more pressure gages adapted respectively to be operated by pressures in different parts of an apparatus in which the several pressures are related factors which enter into the operation of the apparatus; and means correlating thereof show the same reading when a certion predetermined relation exists between the pressures, although said pressures differ from each other in their actual intensities.

" 5. In a pressure-relation gage, the combination with a plurality of liquid-containing 'U-tube ,gages, of a support for said gages upon which they are movably mounted; means for communicating pressures to the free -surfaces of the liquid in each gage,

EBVIN. e. BAILEY. Witnesses JAS. J. MALoNEx, M. E. CovENnY.

said gages so that the indicators 

